In the evolution of digital electronic circuitry many different logic family types have been developed to increase the switching time and throughput of digital processing apparatus. These families, such as diode-transistor, resistor-transistor, and transistor-transistor (T.sup.2 L), etc., have been stepping stones in digital design evolution. At the present time current mode logic (CML) presents the best, economic trade-off between the cost of manufacture and design characteristics. As noted in the first five cross references to this application, the first generation of the CML logic family has been in existence for some time. The next step in the evolutionary process, of which this invention is a part, concerns improvements in the power consumption, switching speed, gate intensity, functionality, and magnitude of integration of the circuits. The development of this second generation CML logic circuitry provides for an enhanced performance of computer system and at the same time lowers the cost-performance ratio of the digital data processor.
In order that this second generation of CML devices may present the maximum throughput improvement possible it was necessary that a large selection of such circuits be available for the designer's use. To this end the applications numbered 6 through 13 in the Cross Reference to Related Application section of the instant application is a measure of the extent of development of this second generation CML circuitry.